GSA Annual Meeting in Seattle, Washington, USA - 2017

Paper No. 84-8
Presentation Time: 9:00 AM-5:30 PM


GRUN, Tobias B.1, VON SCHEVEN, Malte2, BISCHOFF, Manfred2 and NEBELSICK, James H.3, (1)University of Tübingen, Department of Geosciences, Sigwartstraße 10, Tübingen, 72076, Germany, (2)University of Stuttgart, Institute for Structural Mechanics, Pfaffenwaldring 7, Stuttgart, 70550, Germany, (3)University of Tübingen, Department of Geosciences, Sigwartstrasse 10, Tübingen, 72076, Germany,

Clypeasteroid echinoids are well-known to provide skeletons which are robust against both biotic and abiotic stressors such as predators as well as sediment and water agitation. Such structures increase their fossilization potential leading to a rich fossil record. The stress resistance capacity of the test has gained interest in biomimetic research as the mechanisms responsible for the test strength might be serve as biological role models for technical load-bearing constructions in civil engineering. The test of Clypeaster rosaceus has been analyzed to identify and understand the structures that increase test stability and integrity. Imaging techniques such as x-ray micro-computed tomography and scanning electron microscopy have been employed for a detailed insight into the echinoids microstructure. Especially the 3d analyses of the skeleton are essential to understand the functional importance of structures that are not obvious in 2d images. Advanced 3d modelling techniques and finite element analyses revealed that the stereom density distribution and the presence of internal supports follow the expected stress occurrences for simplified smooth pressure loading. Comparative analyses of the virtual models and physical objects indicate that plate interlocking and the system of internal supports play a major role in the strength and robustness of the Clypeaster rosaceus test. Ongoing research concern the significance of stereom density distributions and the microstructural architecture for stiffness and strength. Moreover, actual load occurrences in the ecosystem need to be taken into account in more detail.